1. Field of the Invention
The present invention relates generally to computer drawing applications, and in particular, to a method, apparatus, and article of manufacture for providing and modifying two-dimensional vector fills using topological features/entities.
2. Description of the Related Art
Two-dimensional (2D) vector applications usually provide a means to fill regions. Some 2D vector applications require the user to define closed shapes, and only fill those shapes. Other applications allow the fill to be defined by picking an empty region that is bound by vector curves. Such applications may fill a region bound by curves, but typically, the region becomes fixed as a closed shape. Some applications will allow editing of the closed region, for example when a new curve is placed over a region, the region becomes split. However, the fill for such an application is limited by the closed shape and the fill is modified by modifying the closed shape.
Accordingly, some prior art applications limit the ability to create a fill to closed shapes. Alternative prior art applications allow a user to create curves and create a fill region. However, such applications often create a polygon that is used for the fill. Thereafter, the fill region is edited by editing the polygon. In addition, in such prior art applications, if a fill region is broken (e.g., a curve is moved to create an open shape), the user may be required to manually refresh the page in order to update the fill (i.e., the fill may remain on the screen despite the now broken fill region until a manual update operation is performed). In addition, if after breaking a fill region, the user attempts to draw a curve and create a modified fill region, the fill is not automatically created. Instead, the user must undertake manual operations to create the fill region based on the new curves.
In view of the above, the prior art fails to provide the ability to dynamically update a drawing and modify curves while a fill region (e.g., color or texture) is automatically updated to reflect the modified curves. Further, the prior art fails to provide the ability to dynamically update a fill/fill region that reflects a user's original intent.